The purpose of this study is to design and evaluate a comprehensive, systematic approach to characterizing urban neighborhoods through direct observation of neighborhood characteristics. Public health researchers and practitioners have begun to refocus on the context in which an individual lives as an important determinant of health. Neighborhood characteristics are typically measured through participant self-report, observation (often via video), or secondary databases like the US Census. Major limitations of these approaches include the inability to monitor changes over time, costs and significant staff resources. This has limited their inclusion in more than a few studies and resulted in neighborhoods being evaluated at a single point during a study. Yet, during a multi-year study, the urban neighborhood context may significantly change as a result of seasonality, gentrification, immigration, etc. We propose to evaluate and revise a brief scale, already developed by the research team, aimed at measuring the social, physical and resource environment of urban neighborhoods through direct observation and examine the reliability and validity of the scale. To achieve these aims, we will be working within a larger multi-level parent study aimed at examining the associations between features of the urban environment and mental health, drug use, and HIV risk in 36 NYC neighborhoods that have already been ethnographically defined. We will first define an additional 15 neighborhoods in affluent and/or predominantly white neighborhoods in New York City, as our current sampling frame is overrepresented by neighborhoods with a high prevalence of economic deprivation and minorities. Next, we will use our neighborhood evaluation scale and neighborhood mapping to measure the urban environment. Each of the 51 target neighborhoods will be rated by two independent observers twice a year for 2 years, providing 4 iterations for data collection, analysis and scale revision. Reliability will be assessed via measures of inter-rater and test retest reliability and internal consistency. Problematic items will be eliminated or reworked in the next iteration. The scale will also be assessed for each type of validity. Face validity will be assessed through review by study investigators, consultants and staff. Content validity will be evaluated through internal consistency and evaluation of item values pre- and post-training. Factor analysis will be used to explore the presence and nature of factors. Criterion-related validity will be assessed by video recording and rating a sub-sample of blocks as a "gold standard" for the final iteration of the scale. External construct validity checks comparing the scale results for each neighborhood to key indicators from the US Census (e.g., residential segregation, income inequality) will be performed. In year 2, we will also administer the scale in 50 randomly selected Detroit neighborhoods to evaluate the scale's performance in another urban setting and assess the generalizability. PUBLIC HEALTH RELEVANCE: Public health researchers and practitioners have begun to refocus on the context in which as individual lives as an important determinant of health. Neighborhood characteristics are typically measured through participant self-report, observation (often via video), or secondary databases like the US Census which are limited in their ability to monitor changes over time, are expensive and require significant staffing resources. The purpose of this study is to design and evaluate a comprehensive, systematic approach to characterizing urban neighborhoods through direct observation of neighborhood characteristics that will address these limitations.